Management of Turcicum Leaf Blight of Maize in Himachal Pradesh
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Date
2020-10-07
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palampur
Abstract
Investigations on turcicum leaf blight of maize were undertaken with the objectives to
identify sources of resistance and evaluation of fungicides for its management. The
pathogen on PDA showed grayish to blackish, fluffy growth. The conidia were cylindrical
or straight, 3-8 septate with length varied from 93.5µm to 110.5µm and width ranged from
21.75 to 26.1µm. Observations recorded in disease development revealed that disease
symptoms on leaves first appeared in third week of July as small oval water soaked spots
on lower leaves measuring 0.2 cm in size which gradually increased and attained
maximum elongated size of 12.5 cm x 2.3 cm in second week of September. A total of one
forty four maize inbreds comprising of seventy medium maturing, twenty one early
maturing and fifty three QPM along with two susceptible/moderately susceptible checks
Early Composite and Dhari Local were screened against Exserohilum turcicum under
artificially inoculated conditions. Fifty seven medium maturing, eleven early maturing and
fifty QPM inbreds were found resistant to turcicum leaf blight. In vitro evaluation of
fungicides revealed that propiconazole (Tilt 25EC) and tebuconazole (Folicur) showed
100% mycelial growth inhibition at lowest dose of 50 ppm. Carbendazim (Bavistin 50WP)
and copper oxychloride (Blitox 50 WP) were found least effective. Propiconazole, zineb
and carbendazim 12% + mancozeb 63% were found most effective fungicide which
exhibited 100 per cent spore germination inhibition at 500 ppm. Field evaluation of
fungicides revealed that two sprays of trifloxystrobin 25% + tebuconazole 50% (Nativo)
was most effective resulting in 80.3% disease control with 54.7 percent increase in yield.
However, two sprays of propiconazole was economical and cost effective as compared to
trifloxystrobin 25% + tebuconazole 50% (Nativo).